Air filters in classrooms reduce sick days by more than 10 per cent

School attendance increased by 1.3 days per pupil per year when five elementary schools in Milan, Italy, introduced air filters into classrooms, in the first randomised controlled trial of its kind.

“It’s the first experimental evidence,” says Stefania Renna at the Polytechnic University of Milan. Her team installed high-quality portable air purifiers in 43 randomly chosen classrooms in the schools. Renna describes these as being better than HEPA filters.

The…